IC Determination of Cl^- and NO₃^- in Automobile Tail Gas Purification Catalyst

The sample of automobile tail gas purification catalyst (0.5 g) was ultrasonically extracted with ammonia 3% (φ) solution (30 mL). Cl^- and NO₃^- ion in the extract were separated by IC, using IonPac AS11-HC (4 mm×250 mm) column as separation column and 17 mmol·L^-1 KOH solution as eluant. Restrain conductance detector was used in the determination. Linear relationships between values of peak height and mass concentration of Cl^- and NO₃^- were kept in the same range of 0.1-10.0 mg·L^-1, with detection limits of Cl^- and NO₃^- of 0.004, 0.019 mg·L^-1 respectively. The proposed method was applied to the analysis of substantial samples and recovery was tested by standard addition method, giving values of recovery in the range of 98.8%-116% and RSD's (n=7) no more than 2.0%.